The goal of this research is to publish an assessment battery for normal and disabled children from 2 1/2 to 7 years of age and to make it available to clinicians, educators, and researchers. The battery will incorporate three innovative features, important for effective assessment of children's cognitive functioning, that are not included on any other early childhood assessment battery. These features are: 1) Assessment of a broad range of abilities; 2) Assessment of abilities as separately as possible; 3) Assessment of the same abilities across the entire age range of the test. These features make possible the identification of a child's cognitive strengths and weaknesses, the use of a single subtest to assess a particular ability, and the evaluation of intellectual growth longitudinally. The goal of Phase 1 work would be the construction of the assessment battery, utilizing data already obtained from the testing of a national sample of children on eleven tasks that assess central components of cognitive and neurological functioning. Item Response Theory and the three-parameter statistical model would be used to arrive at a set of scales that have the best statistical qualities across the age and ability range covered by the test.